Ketorolac tromethamine compositions for treating or preventing ocular pain

ABSTRACT

Compositions comprising ketorolac tromethamine at a therapeutically effective concentration of less than 0.5% are disclosed herein. Methods of treating or preventing ocular pain using said compositions are also disclosed herein.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/434,956, filed Mar. 30, 2012, which is acontinuation of U.S. patent application Ser. No. 11/842,915, filed Oct.17, 2007, now U.S. Pat. No. 8,207,215, issued Jun. 26, 2012, which is acontinuation application of U.S. patent application Ser. No. 10/856,192,filed May 28, 2004, now U.S. Pat. No. 8,008,338, issued Aug. 30, 2011,which claims priority to U.S. Provisional Patent Application Ser. No.60/475,683, filed Jun. 3, 2003, all of which are hereby incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to pharmaceutical compositions. Moreparticularly, this invention relates to topical ophthalmic compositionscomprising 5-benzoyl-2,3-dihydro-1H-pyrrolizine-1-carboxylic acid,otherwise known as ketorolac.

2. Description of the Related Art

Topical nonsteroidal anti-inflammatory drugs (NSAIDs) are used tocontrol pain and postoperative inflammation. All drugs are associatedwith some adverse effects. With the use of NSAIDS in topical ophthalmictreatment of patients, surface toxicity has been a concern, andincidents of keratitis, corneal subepithelial infiltrates, ulceration,and corneal melts have been reported (Guidera et al, Ophthalmology,2001, 108 (5), pp. 936-944; Solomon et al, J Cataract Refract Surg,2001, 27 (8), pp. 1232-1237; Teal et al, J Cataract Refract Surg, 1995,21(5) , pp. 516-518). Further, patients often report burning or stingingon instillation (Jaanus et al, Antiinflammatory Drugs. Clinical OcularPharmacology, Bartlet, J. D. and Jaanus, S. D., Ed., Boston: Heineman,2001, pp. 265-298). The burning or stinging could be related to theconcentration of the active component of the formulation.

Ketorolac tromethamine 0.5% (w/v) ophthalmic solution, available fromAllergan, Inc., under the tradename ACULAR®, is a safe and effectiveNSAID with proven analgesic and anti-inflammatory activity. The mostcommon adverse event associated with the use of the 0.5% ketorolacformulation is ocular irritation, primarily burning, and stinging oninstillation. Eliminating or reducing ocular irritation has thepotential for improving tolerability, compliance, and effectiveness oftreatment.

BRIEF SUMMARY OF THE INVENTION

We have surprisingly discovered that reducing the concentration ofketorolac tromethamine reduces the occurrence of adverse events whilemaintaining clinical efficacy. Additionally, we have also discoveredthat the reduced concentration of ketorolac tromethamine offerssurprising benefits in terms of formulation in that significantly lesspreservative, chelating agent, and surfactant are required for effectiveformulation.

Compositions comprising ketorolac tromethamine at a therapeuticallyeffective concentration of less than 0.5% are disclosed herein. Thisinvention relates to an aqueous topical ophthalmic compositioncomprising from 0.35% to 0.45% ketorolac tromethamine. Another aspect ofthis invention relates to a method of treating or preventing ocular painin a person comprising topically administering to said patient a sterilecomposition comprising from 0.35% to 0.45% ketorolac tromethamine.

While not intending to limit the scope of this invention in any way, ofparticular interest in relationship to this invention is the use ofaqueous topical ophthalmic compositions of 0.4% (w/v) ketorolactromethamine for the treatment of ocular pain, especially for thetreatment of ocular pain in postoperative photorefractive keratectomy(PRK) surgery patients. It is surprising that the 20% lowerconcentration of ketorolac as compared to the above ACULAR® productwould reduce the incidence of adverse events and enhance comfort whilemaintaining clinical efficacy.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1: Effect Of Ketorolac 0.4% On Pain Intensity During First 12 HoursPost-Postoperative Photorefractive Keratectomy (PRK) Surgery.

FIG. 2: Time Course for First Achieving “No Pain” With Ketorolac 0.4% vsVehicle.

FIG. 3: Percentages of Ketorolac 0.4%—and Vehicle-Treated PatientsExperiencing Complete or Great Pain Relief Post-PRK.

FIG. 4: Percentages of Ketorolac 0.4%—and Vehicle-Treated PatientsRequiring Escape Medication.

FIG. 5: Rate of Re-epithelialization.

DETAILED DESCRIPTION OF THE INVENTION

All of the aqueous topical ophthalmic compositions of this invention arecontemplated for use in treating or preventing ocular pain. Preferably,all of the compositions of this invention are contemplated for use whensaid ocular pain is a result of photorefractive keratectomy surgery(PRK).

On important aspect of this invention is that these compositions have aconcentration of ketorolac tromethamine which is optimized to reduceside effects and improve ease of formulation, while maintaining clinicalefficacy in treating ocular pain. As such, the concentration ofketorolac tromethamine in compositions related to this invention shouldbe from 0.35% to 0.45%. Preferably the concentration of ketorolactromethamine in the aqueous topical ophthalmic composition of thisinvention is 0.4% ketorolac tromethamine.

The fact that the concentration of ketorolac tromethamine incompositions related to this invention is optimized for ease offormulation is underscored by the surprising observation thatcompositions of the present invention can be prepared with significantlylower concentrations of preservative, surfactant, and chelating agentthan is possible with compositions containing slightly higherconcentrations of ketorolac tromethamine.

The term preservative has the meaning commonly understood in theophthalmic art. Preservatives are used to prevent bacterialcontamination in multiple-use ophthalmic preparations, and, while notintending to be limiting, examples include benzalkonium chloride,stabilized oxychloro complexes (otherwise known as PURITE®),phenylmercuric acetate, chlorobutanol, benzyl alcohol, parabens, andthimerosal. Preferably, the preservative is benzalkonium chloride.

The term surfactant used in this invention has the meaning commonlyunderstood in the art. Surfactants are used to help solubilize thetherapeutically active agent or other insoluble components of thecomposition. Anionic, cationic, amphoteric, zwitterionic, and nonionicsurfactants may all be used in this invention. Preferably, a nonionicsurfactant is used in this invention. While not intending to limit thescope of the invention, some examples of useful nonionic surfactants arepolysorbates, poloxamers, alcohol ethoxylates, ethylene glycol-propyleneglycol block copolymers, fatty acid amides, and alkylphenol ethoxylates,and phospholipids. Most preferably, the surfactant is an octylphenolethoxylate with an average of 40 ethoxylate groups. This type ofsurfactant, also known as octoxynol-40 or IGEPAL® CA-897, can bepurchased under the IGEPAL® CA-897 tradename from Rhone-Poulenc.

The term chelating agent refers to a compound that is capable ofcomplexing a metal, as understood by those of ordinary skill in thechemical art. Chelating agents are used in ophthalmic compositions toenhance preservative effectiveness. While not intending to be limiting,some useful chelating agents for the purposes of this invention areedetate salts like edetate disodium, edetate calcium disodium, edetatesodium, edetate trisodium, and edetate dipotassium. In the preferredembodiment of this invention edetate disodium is used as the chelatingagent.

In addition to surfactants, preservatives, and chelating agents,tonicity agents and other excipients are often used in ophthalmiccompositions. Tonicity agents are often used in ophthalmic compositionsto adjust the concentration of dissolved material to the desiredisotonic range. Tonicity agents are known to those skilled in theophthalmic art, and, while not intending to be limiting, some examplesinclude glycerin, mannitol, sorbitol, sodium chloride, and otherelectrolytes. Preferably, the tonicity agent is sodium chloride.

One preferred embodiment of this invention relates to an aqueous topicalophthalmic composition comprising 0.4% ketorolac tromethamine, from0.001% to 0.05% edetate disodium, from 0.004% to 0.007% benzalkoniumchloride, and from 0.001% to 0.005% Octoxynol-40.

Another preferred embodiment of this invention relates to an aqueoustopical ophthalmic composition comprising 0.4% ketorolac tromethamine,0.006% benzalkonium chloride, 0.015% edetate disodium, 0.003%Octoxynol-40, 0.79% sodium chloride, and an effective amount of sodiumhydroxide or hydrochloric acid to adjust the pH to from 7.2 to 7.6.

Another preferred embodiment of this invention relates to an aqueoustopical ophthalmic composition consisting essentially of 0.4% ketorolactromethamine, 0.006% benzalkonium chloride, 0.015% edetate disodium,0.003% Octoxynol-40, 0.79% sodium chloride, and an effective amount ofsodium hydroxide or hydrochloric acid to adjust the pH to from 7.2 to7.6.

The most preferred embodiment of this invention relates to an aqueoustopical ophthalmic composition consisting of 0.4% ketorolactromethamine, 0.006% benzalkonium chloride, 0.015% edetate disodium,0.003% Octoxynol-40, 0.79% sodium chloride, and an effective amount ofsodium hydroxide and/or hydrochloric acid to adjust the pH to from 7.2to 7.6.

Example 1

Unless otherwise specified, all steps in this procedure were carried outat room temperature. The following procedure was followed in accordancewith the amounts listed in Table 1 below. Purified water at 90% of batchsize was charged into the main batch vessel. Mixing was initiated toproduce a vortex sufficient to disperse and/or dissolve all productingredients without excessive aeration or foam formation. The followingcomponents were added directly into the vortex in order, allowing eachto dissolve before adding the next: sodium chloride, edetate disodium,octoxynol-40 (as a 70% stock solution) and benzalkoniurn chloride (as a10% stock solution). The amount of benzalkonium chloride added took intoaccount the assay of the stock solution used. The solution was mixed forno longer than 15 minutes. A specified amount of 1N sodium hydroxide,1.85 mL per liter of final bulk product, was then added. The pH waschecked and if needed was adjusted to 10.7-11.0 with 1N sodium hydroxideor 1N hydrochloric acid. Ketorolac tromethamine was then added based on“as is” assay and mixed until completely dissolved based on visualinspection. When dissolved, the solution pH was again checked and ifneeded adjusted to pH 7.3-7.5 (final target pH is 7.4) with 1N sodiumhydroxide or 1N hydrochloric acid. Purified water was then added tobring the bulk solution to final volume and allowed to mix for at least15 minutes to ensure uniformity. The solution was then sterile filteredfor use.

TABLE 1 0.4% Ketorolac Tromethamine Ophthalmic Solution KetorolacTromethamine  0.4% Edetate Disodium 0.015% NaCl  0.79% BenzalkoniumChloride 0.006% Octoxynol-40 0.003% Ph 7.4

Example 2

Table 2 contains the composition of an ophthalmic solution containing0.5% ketorolac tromethamine which is clinically effective for treatingocular pain following photorefractive keratectomy surgery. Thecomposition was prepared by the same procedure as Example 1. Thiscomposition was optimized to minimize the amounts of chelating agent,preservative, and surfactant required, since they are irritating to theeye. Comparison of the 0.5% solution of Table 2 to the 0.4% solution ofTable 1 reveals that, surprisingly, the reduction of the amount ofchelating agent, preservative, and surfactant required for the 0.4%ketorolac tromethamine is significantly greater than 20%, whichcorresponds to the reduction in the therapeutic agent.

TABLE 2 0.5% Ketorolac Tromethamine Ophthalmic Solution KetorolacTromethamine  0.5% Edetate Disodium  0.10% NaCl  0.79% BenzalkoniumChloride 0.010% Octoxynol-40 0.007% pH 7.4

Example 3

A multicenter, randomized, double-masked, vehicle-controlled,parallel-group study was carried out using the 0.4% ketorolactromethamine formulation of Example 1. The study subjects consisted of157 patients (78-79/group) undergoing unilateral PRK surgery. The keyinclusion criteria for the study were that each subject a) was acandidate for unilateral photorefractive keratectomy surgery (PRK)within 7 days after the initial visit, b) had best-corrected ETDRSvisual acuity of 20/100 or better, and c) was capable of wearing a softbandage contact lens. Key exclusion criteria were a history ofrefractive ocular surgery and sensitivity to study medication or itsvehicle, TYLENOL® #3, or OCUFLOX®. The patient demographics are shown inTable 3. A total of 157 patients were enrolled with an age range of20-66 years. There were no significant demographic differences betweentreatment groups.

TABLE 3 Patient Demographics n % Gender Female 91 58 Male 66 42 Age,mean ± SD 39 ± 10 Race Caucasian 148 94 Black 5 3 Hispanic 2 1 Asian 1 1Other 1 1

Each subject received OCUFLOX® 5 min prior to study medication. Thestudy subjects then received ketorolac tromethamine 0.4% ophthalmicsolution or vehicle, 1 drop QID for up to 4 days, and the controlsubjects received the vehicle (i.e. the composition of Table 1 withoutthe ketorolac tromethamine). The all subjects were then instructed totake TYLENOL® #3 as needed for intolerable pain (escape medication).Patients used electronic diaries with date and time stamp to record theocular pain they experienced as one of the following: no pain, mild,moderate, severe, intolerable.

FIG. 1 shows that the pain intensity was significantly less for thesubjects who received ketorolac tromethamine 0.4% (P≦0.001) during thefirst 12 hours post-PRK compared to those who received the vehicle only.In particular, during the first 12 hours post-PRK, the group thatreceived 0.4% ketorolac tromethamine had fewer patients with severe orintolerable pain (43.0%, 34/79) compared with the vehicle group (87.2%,68/78, P≦0.001). In particular, the median pain intensity reported bythe group which received 0.4% ketorolac tromethamine was 1 grade lessthan with the group which received the vehicle only (moderate vs severeon a 5-point scale of 0=no pain to 4=intolerable pain). This 1-gradedifference was considered clinically significant. Additionally, painintensity was also significantly less for the group which receivedketorolac tromethamine compared with the group which received thevehicle only at 12-48 hours post-PRK (P≦0.001, data not shown).

FIG. 2 shows that the onset of pain relief was faster with the groupthat received 0.4% ketorolac tromethamine compared to the group thatreceived the vehicle only (P≦0.001). The median time to first report ofno pain was 18-24 hours in the 0.4% ketorolac tromethamine groupcompared with 48-54 hours for the group which received vehicle only(P≦0.001). Furthermore, the initial experience of no pain during thefirst 12 hours post-PRK was reported by 44.3% (35/79) of patients in theketorolac tromethamine group compared with 7.8% (6/78) of patients inthe vehicle group.

FIG. 3 shows that significantly more of the patients who received 0.4%ketorolac tromethamine reported complete or pain relief thanvehicle-treated patients throughout the study up to 84 hours.

In addition to experiencing greater and significantly faster pain reliefoverall than the vehicle group, the patients who received ketorolactromethamine also had less incidents of severe pain, as demonstrated bythe significantly lower number of ketorolac tromethamine patients whoused the escape vehicle. FIG. 4 shows that during the first 12-hourspost-PRK, the escape medication was taken by only 46.8% (37/79) of theketorolac tromethamine patients compared to 92.3% (72/78; P≦0.001) ofthe vehicle patients. Additionally the 0.4% ketorolactromethamine-treated patients used significantly less escape medication12-48 hours post-PRK compared with vehicle-treated patients (P≦0.006).

The rate of corneal re-epithelialization was also studied for bothgroups, as depicted in FIG. 5. Although corneal re-epithelializationoccurred more quickly in the vehicle group than in the ketorolac group(P=0.016), the difference was probably not clinically significant. Themedian time to re-epithelialization was between days 2 and 3 followingPRK surgery for both treatment groups.

TABLE 4 Adverse Events (Treatment-Related and Unrelated) Ketorolac 0.4%Vehicle Frequency (%) Frequency (%) n = 79 n = 78 Eye Pain 3 (3.8) 4(5.1) Headache 1 (1.3) 2 (2.6) Corneal Infiltrates 1 (1.3) 1 (1.3) EyeEdema 1 (1.3) 0 (0.0) Conjunctival Hyperemia 1 (1.3) 0 (0.0) Cornea 0(0.0) 1 (1.3) Nausea 0 (0.0) 3 (3.8) Nausea/Vomiting 0 (0.0) 2 (2.6)Vomiting 0 (0.0) 1 (1.3) Rhinitis 0 (0.0) 1 (1.3)

Table 4 shows that adverse events were minor and infrequent for thegroup that received ketorolac tromethamine. Ocular irritation was notreported, and the ketorolac tromethamine group actually had less adverseevents than the vehicle group. At least 1 adverse event was reported foronly 6.3% of 0.4% ketorolac tromethamine-treated patients (5/79)compared to 15.4% of vehicle-treated patients (12/78). Furthermore, only1.3% of 0.4% ketorolac tromethamine-treated patients (1/79) werediscontinued from the study due to adverse events compared to 7.7% ofvehicle-treated patients (6/78). Changes in visual acuity andbiomicroscopic findings in the subjects were as expected post-PRK.

In summary, the 0.4% ketorolac formulation is clinically effective intreating post PRK ocular pain. In comparison with vehicle-treatedpatients, the 0.4 ketorolac tromethamine-treated patients experiencedsignificantly greater and faster pain relief (P≦0.001), and usedsignificantly less escape medication compared to vehicle-treatedpatients (P≦0.006). Additionally, the 0.4% ketorolac tromethamineformulation has an excellent tolerability profile. Adverse events wereminor and infrequent.

Example 4

A comfort study was carried out to compare the ocular comfort of theketorolac tromethamine solution 0.4% with that of a compositioncontaining the composition of Table 5 in healthy volunteers. Thecomposition is the same as that in Table 5 except that no preservativewas used, as is a single use formulation.

TABLE 5 0.5% Non-Preserved Ketorolac Tromethamine Ophthalmic SolutionKetorolac Tromethamine  0.5% Edetate Disodium 0.10% NaCl 0.79%Octoxynol-40 0.007%  pH 7.4

A single center, randomized, investigator-masked, paired-comparisonclinical trial was carried out. Forty-five subjects were randomized toreceive a single drop of the composition of Table 1 (Formula 1) in oneeye and the composition of Table 5 (Formula 2) in the contralateral eyeat two evaluations on a single day. Before and after receiving theirfirst set of drops, subjects were asked to rate their ocular discomforton a scale of 0 to 4, where 0=no discomfort and 4=a definite continuousburning/stinging that last more than 30 seconds. The procedure wasrepeated 5 minutes after the first set of drops were instilled.

The mean subject discomfort score prior to each drop instillation was 0.Both Formula 1 and Formula 2 were reported to be comfortable, with amean discomfort score of 0.93 in the Formula 1 group and 0.96 in theFormula 2 group after the first drop instillation (P=0.881). After thesecond drop instillation, subjects reported that Formula 1 was morecomfortable than Formula 2. The mean score was 0.53 in the Formula 1group, compared with a mean score of 0.87 in the Formula 2 group(P=0.017).

Formula 1 is at least as comfortable upon instillation as Formula 2. Ina multi-use formulation such as that of Table 2, it is expected that a0.4% ketorolac tromethamine solution prepared as disclosed herein willbe significantly more comfortable than a 0.5% ketorolac tromethaminesolution, while the clinical efficacy of the two compositions areessentially the same.

What is claimed is:
 1. A method of treating ocular pain in a patient,the method comprising the step of administering at least once daily toan eye of the patient a first composition comprising about 0.4% w/vketorolac tromethamine, wherein the method reduces ocular pain andresults in less ocular side effects as compared to the at least oncedaily administration to an eye of a second composition comprising 0.5%w/v ketorolac tromethamine.
 2. The method of claim 1, wherein the sideeffects include at least one side effect from the group consisting ofstinging, foreign body sensation or both.
 3. The method of claim 1,wherein the method reduces inflammation in the eye of the patient. 4.The method of claim 1, wherein the method comprises the step ofadministering four times daily to an eye of the patient a firstcomposition comprising about 0.4% w/v ketorolac tromethamine, whereinthe method reduces ocular pain and results in less ocular side effectsas compared to the four times daily administration to an eye of a secondcomposition comprising about 0.5% w/v ketorolac tromethamine.
 5. Themethod of claim 1, wherein administration of the first compositionresults in increased ocular comfort as compared to the administration tothe eye of the second composition.
 6. The method of claim 3, whereinadministration of the first composition results in increased ocularcomfort as compared to the administration to the eye of the secondcomposition.
 7. The method of claim 1, wherein the first composition isas effective in treating ocular pain as the second composition, despitehaving a lower concentration of ketorolac tromethamine.
 8. The method ofclaim 1, wherein the side effects include at least one side effectselected from the group consisting of ocular irritation, ocular burningand ocular stinging.
 9. The method of claim 1, wherein theadministration is by topical instillation.
 10. The method of claim 1,wherein the first composition comprises edetate disodium.
 11. The methodof claim 1, wherein the person is experiencing ocular pain due tocorneal refractive surgery.
 12. The method of claim 1, wherein themethod results in analgesic activity to the patient's eye.
 13. Themethod of claim 1, wherein the method reduces pain and ocular stingingafter ophthalmic surgery.
 14. The method of claim 13, wherein thesurgery is corneal refractive surgery.
 15. The method of claim 1,wherein the method reduces ocular burning after ophthalmic surgery.